Knife sharpener



Nov. 18, 1958 W. A. LEBUS KNIFE SHARPENER Original Filed July 26, 1955 a W a? w 5 a n IIIHIHHIIIIHIW IN VEN TOR.

United States tent KNIFE SHARPENER William A. Lebus, Riverside, Ill.

Continuation of application Serial No. 524,360, July 26, 1955. This application August 19, 1957, Serial No. 678,991

14 Claims. (Cl. 51102) This invention relates to a knife and scissors sharpener and more particularly to a device of the type indicated which is adapted to impart a uniform cutting edge to a scissors blade at a predetermined angle thereto.

This application is a continuing application of my application Serial No. 524,360, filed July 26, 1955, now abandoned.

Gne of the difliculties in the use of currently available sharpeners is that of maintaining a proper alignment of the scissors blade with the grinding wheel in order to produce a cutting edge having a uniform angle to the plane of the blade.

Another problem is derived from the fact that the cutting edge of the blade normally contacts the wheel at a single tangential point at a given moment so that variation in the speed at which the blade is moved over the wheel can create a considerable difference in the amount of material removed from the cutting edge'at various positions longitudinally.

Another problem is that the scissors blade may be inserted in the sharpener so far that the grinding wheel will be abraded by the back end of the blade or by the blade which is not being sharpened so as to impair its usefulness.

It is accordingly an object of the invention to provide a knife and scissors sharpener having spring means which are adapted to maintain a scissor blade in proper align ment with the grinding wheel during sharpening.

Another object is to provide a grinding wheel having a circumferential edge which is tapered at a predetermined angle relative to the axis of the wheel, so that the blade will have a cutting edge formed thereon at a correct angle relative to the plane of the blade.

Another object is to provide a suitable housing construction for the sharpener having guide means formed thereon adapted to guide the blade at a predetermined angle to the plane of the wheel, so that the cutting edge of the blade may contact the tapered edge of the wheel over a relatively large portion of its surface longitudinally, thereby avoiding the aforementioned inequalities in the surface of the cutting edge.

Another object is to provide a housing as described having a shoulder element adapted to prevent insertion of the blade into the sharpener beyond the cutting edge thereof, thereby eliminating the aforementioned undesirable abrasion of the wheel.

Still another object is to provide support means for the aforementioned spring element adapted to position the spring firmly against the blade and thereby enable the spring to hold the blade snugly against the aforementioned guide means regardless of the variation in the thickness and width of the blade which occurs as the blade is moved axially over the abrasive wheel.

Yet another object is provision of an abrasive wheel and support and guide means associated therewith whereby a scissors blade may be sharpened on the peripheral edge of the wheel, so that the blade is not jerked upwardly as occurs where the side of the wheel is used for this purpose.

Other objects and advantages of the invention will appear as the description proceeds in accordance with the drawings, in which:

Fig. l is a side elevational view of a knife and scissors sharpener according to the invention;

Fig. 2 is a top plan view of the sharpener of Fig. l; and

Fig. 3 is a vertical sectional and fragmentary view of the blade positioning means according to the invention taken along the line 3-3 of Fig. 2.

Referring now to Fig. 1, the knife and scissors sharpener 19 includes a casing 12 which may be formed of plastic or other suitable material and comprises a boxlike motor housing 14 enclosing a motor 16, a ring-like base 18 of a substantially rectangular form and an abrasive wheel housing 20 of reduced height and having openings 22 and 24 in the form of guide ways formed therein. The motor unit 16 is provided with a shaft 26 extending into the wheel housing 20 and on this shaft is mounted a grinding wheel 27 in register with the guide way 22 and a grinding wheel 28 in register with the guide way 24. The wheel 27 is constructed and arranged for sharpening knives, while the wheel 28 is particularly suitable for sharpening scissors, shears and the like.

The grinding wheel 28 is provided with a circumferential edge portion 48, which is tapered, as shown more particularly in Figs. 1 and 3, for purposes hereinafter further described. The housing is bevelled along its front edge to provide a facing 50 disposed tangentially to the wheel 28 and is provided with a cut-out portion 52 adapted to receive the wheel.

A shoulder 54 depends from the top surface of the housing 20 and defines one side of the guide way 24. The shoulder 54 extends transversely of the housing at a predetermined angle to the plane of the wheel 28 and in partially overlying relation thereto. A second and substantially parallel shoulder 56 forms the other side of the guide way 24. A spring element 58, having an elongated depending flange 68 is secured to the side of the housing opposite the facing 50, preferably'by means of a tab 64) bolted in a recess 62 by means of a suitablev bolt 64. The spring is curved around the corner portion 66 of the housing but is biased away from shoulder 56 so that the free extremity of the spring 58 normally bears against the shoulder 54 and the flange 68 thereof is disposed diagonally between the shoulders.

The spring 58 is also provided with a flange 70 formed integrally with the flange 68, at an angle corresponding to the angle of taper of the edge 48 on the wheel 28 and as best seen in Fig. 3, this flange 70 is adapted to ride on a tapered nodule 72 adjacent the shoulder 56. The nodule 72 is preferably disposed in a recess or shelf 74 formed along the upper marginal edge of the shoulder 56, and desirably intermediately of the extremities of the recess. The surface of the nodule 72 preferably is sloped to correspond to the angle of the flange 70 and the edge 48. Accordingly, when a blade 76 to be sharpened is inserted between the spring 58 and the shoulder 54, as shown in Fig. 3, and is moved forward along its longitudinal axis, the spring will hold the blade in abutment with the shoulder 54, the nodule 72 preventing the flange 70 from moving loosely in the recess 74, so that the spring is always in secure contact with the blade and so that the bottom edge of the flange 68 transverses a path in close spaced relation to the edge portion 48.

The angle formed by the shoulder 54 and the plane of the wheel 28 is such that a relatively large amount of the surface of the cutting edge 78 of the scissors blade will be in contact with the tapered edge 48 at successive positions as the blade is moved across the wheel 28, since the diagonal position of the blade will permit it to contact a flatter surface than would be the case with the blade aligned in the plane of the wheel. The fact that a greater length of surface ofiedge '78 is being sharpened at each instant minimizes irregularities due to differences in the speed at which the blade is moved over the wheel or variations in pressure on the blade. The surface {of the shoulder 54 is desirably inclined at a slight angle to the vertical so that a scissors blade may be positioned in the guide way with its central plane in a vertical position. In any event, however, the inclination of this should bear a predetermined relation to the angle of tapers of edge 43.

The problem of positioning the blade at exactly the right angle to the wheel in order to achieve a proper in clination of'the cutting edge has been solved by creating a taper 48 in the Wheel itself which eliminates the necessity of tilting the blade in awkward positions. Thus the taper 48 converges downwardly toward shoulder 54, in predetermined relation thereto, at an angle to the axis of the shaft 26 which assures that a proper angle for the cutting edge 78 will be maintained when the blade is held against the shoulder by spring 58.

It is ordinarily very difficult to insert the scissor blade in the sharpener to the exact extent necessary for honing the entire cutting edge without causing the blunt end portion of the blade or portions of the other blade to abrade the surface 48 and render it uneven. A shoulder 30 is therefore formed integrally with shoulder 54 and in offset relation thereto, which is effective to prevent insertion of the blade too far in between flanges 54 and 56 and will abut the blade not being sharpened When the blade 76 has been sharpened completely. Thus the angle between the shoulder 80 and the horizontal corresponds to the usual angle between scissor blades when fully opened.

A platform 82 is preferably formed between the lower marginal edges of the flanges 54 and 56 and integral therewith, which may serve to limit downward movement of blade 76 as it is moved forward along its longitudinal axis so as to preserve the advantages of uniform sharpening action provided by the spring 58 as it rides on nodule 72 to hold the blade firmly against shoulder 54- and in proper alignment with the taper 48.

Also, it is preferred that the shoulder 54 and the depending flange 68 of the spring 58 be inclined toward one another slightly in downwardly conver ing relationship corresponding to the usual inclination of the sides 84 and 88 of blade 76, in order to hold the blade firmly against lateral movement.

The angle of the taper 48 and the complementary angle of the shoulder 54 tothe plane of the wheel 28 may be varied to effect varying inclinations in the cutting edge 84, but it will be understood that once the blade is positioned between the shoulder 54 and the spring 58 the correct angle for the edge will be produced automatically.

The opening 22 for the wheel 27 extends from side to side of the housing and has downwardly and inwardly converging aprons 30 extending from each margin and from end to end of the opening. Also the aprons converge in the transverse direction of the housing so that the near-side opening as seen in Fig. 2 is narrower than the far side opening and both side openings are considerably narrower at the bottom than at the top. These aprons 30 serve as guiding surfaces against which a knife to be sharpened is rested as it is drawn along the side surfaces of the wheel 27 and the angles of these surfaces from the vertical may be /2 and 13", respectively, to provide the most desirable angles for opposed faces of the cutting edge of a knife. Also horizontal spring arms 31 mounted on a vertical column or post 32 at the far end of the opening are provided to urge the blade against the aprons and keep it from engaging the wheel except along the cutting edge to be sharpened.

The motor enclosing portion of the housing extends over substantially one half of the length of the unit and is provided with a cover portion 33 of preferably rectangular configuration which is set in sidewalls 34 and 36 by means of structure set forth in my copending application Ser. No. 428,068 and is mounted on suitable spring elements for making and breaking the circuit of the motor when the cover is depressed or released. The motor unit is mounted on one leg 48 of an upright U-shaped bracket 38, the motor shaft 26 extending longitudinally through the opposite leg 42 of the bracket 38, in which the shaft is journalled in a suitable bearing 44. As seen in Fig. l, the wall 4-2 is mounted between the grinding wheels in order to provide adequate support therefor, and the shaft 26 has a fan 46 fixedly secured thereto.

Although I have described my invention with reference to particular features and advantages thereof, it will be obvious to those skilled in the art that modifications in the details and principles of the invention may be made without departing from the essential concept thereof as set forth in the following claims.

I claim:

1. In a scissors sharpener having a motor casing, a motor mounted within said casing, said motor having a rotatable shaft and an abrasive wheel carried by said shaft,

5 a shoulder formed integrally with said casing and extending into partially overlying relation with said wheel at a predetermined angle relative to the plane of said wheel, a second shoulder extending in substantially parallel spaced relationship to said first shoulder to form a guide way, and a spring secured at one end of said second shoulder and biased into normally abutting engagement with said first named shoulder, said spring having an elongated depending flange extending between said shoulders and having an inclination complementary to the inclination of said first shoulder whereby said spring and said first shoulder are adapted to snugly engage a blade inserted therebetween with said spring affording pivotal compensating movement during axial movement of the blade.

2. A knife and scissors sharpener having a casing including a motor enclosing portion and a wheel housing portion and a motor and a wheel rotatable by said motor, said wheel having a tapered periphery, a diagonally extending opening in the top portion of said wheel housing and a pair of depending and substantially parallel spaced shoulders formed in said opening, a recess extending along one marginal edge of said shoulders, a guide and support nodule disposed in said recessed portion, a spring secured to a side of said wheel housing portion and extending diagonally in said opening and into normally abutting relation with the other of said shoulders, said spring being provided with an elongated depending flange and a second flange integrally formed therewith adapted to ride on said nodule during sharpening of said blade on said wheel, so that the lower edge of said first flange travels along a path in proximate spaced relation to the periphery of said wheel.

3. In a knife and scissors sharpener having a motor, a casing and a wheel rotatable by said motor, said casing including a wheel housing portion, said housing having a diagonally extending opening forming a guide way and defined in part by a shoulder formed integrally with said housing and extending into overlying relation with said wheel, said shoulder having a predetermined inclination toward the plane of said wheel, a spring resiliently mounted in predetermined spaced relation to one end of said shoulder and extending into normally abutting relation with said shoulder at the other end of said shoulder and a second shoulder having a guide and support nodule for said spring, said spring being configured to ride thereupon in predetermined complementary alignment to said first shoulder.

4. In a knife and scissors sharpener having a casing, a motor and a grinding wheel rotatable by said motor, said .wheel being mounted in a housing forming a part of said casing, an opening defined by a pair of depending shoulders formed integrally with said housing and extending into partially overlying relation with said grinding wheel, said shoulders being spaced apart a predetermined distance and extending in substantially parallel relation at a predetermined angle to the plane of said wheel, an abutment shoulder formed in said housing at a prede termined angle to one of said shoulders and integral therewith, a circumferential edge on said wheel having a predetermined taper, a recessed shelf formed substantially horizontally along the upper marginal edge of the other of said shoulders, a nodule having a taper corresponding in configuration and direction to the taper of said wheel disposed on said shelf, and a spring having a depending flange extending diagonally between said shoulders into normally abutting relation'with said one shoulder, said spring having a flange formed integrally with said first flange and disposed at an angle corresponding to the taper of said nodule and said wheel so that said depending flange clears the edge of said wheel when a scissor blade is passed between said one shoulder and saiddepending flange.

5. In a knife and scissors sharpened having a motor, a housing and an abrasive wheel rotatable by said motor, a circumferential edge on said wheel having a predetermined taper relative to the axis of said wheel, a pair of substantially spaced parallel shoulders forming a guide way in said casing extending into partially overlying relation with said wheel at a predetermined angle to the plane of said wheel, and spring means adapted to bear resiliently against a blade inserted between said spring and one of said shoulders, said spring extending substantially diagonally between said shoulders with a free end thereof normally contacting one of said shoulders and the other end thereof being anchored at an extremity of the other of said shoulders, said spring comprising an elongated depending flange and a flange formed integrally therewith, said spring being pivotally responsive to movement of a blade longitudinally across said wheel to maintain full abutting engagement with the blade with said second flange guided by said other shoulder.

6. In a knife and scissors sharpener having a motor, a housing and an abrasive wheel rotatable by said motor, a circumferential edge on said wheel having a predetermined taper relative to the axis of said wheel, a pair of substantially spaced parallel shoulders forming a guide way in said casing extending into partially overlying relation with said wheel at a predetermined angle to the plane of said wheel, and spring means adapted to bear resiliently against a blade inserted between said spring and one of said shoulders, said spring extending substantially diagonally between said shoulders, at free end of said spring normally contacting one of said shoulders adjacent one extremity thereof and the other end of said spring being anchored at an extremity of the other of said shoulders, said spring comprising an elongated depending fiange and a flange formed integrally therewith, said other shoulder being recessed along its upper marginal edge and having a tapered guide and support nodule formed in the recessed portion and in abutting relation with said second named flange whereby to maintain said spring in firm alignment with said one shoulder during pivotal movement of said spring in response to movement of a blade longitudinally across said wheel.

7. In a scissors sharpener having a motor casing, a motor mounted within said casing, said motor having a rotatable shaft and an abrasive wheel carried by said shaft, a shoulder formed integrally with said casing and extending into partially overlying relation with said wheel at a predetermined angle relative to the plane of said wheel, a second shoulder extending in substantially parallel spaced relationship to said first shoulder to form a guide way, and a spring secured at one end of said second shoulder and biased into normally abutting engagement with said first named shoulder, said spring having an elongated depending flange extending between said shoulders and having an inclination complementary to the inclination of said first shoulder thereby said spring and said first shoulder are adapted to snugly engage a blade inserted therebetween with said spring affording pivotal compensating movement during axial movement of the blade, said spring providing a second flange extending substantially horizontally over said second shoulder and adapted to be maintained thereby in firm alignment with said first shoulder during said pivotal movement of said spring.

8. In a scissors sharpener having a motor casing, a motor mounted within said casing, said motor having a rotatable shaft and an abrasive wheel carried by said shaft, a shoulder formed integrally with said casing and extending into partially overlying relation with said wheel at a predetermined angle relative to the plane of said wheel, a second shoulder extending in substantially parallel spaced relationship to said first shoulder to form a guide way, and a spring secured at one end of said second shoulder and biased into normally abutting engagement with said first named shoulder, said spring having an elongated depending flange extending between said shoulders and having an inclination complementary to the inclination of said first shoulder whereby said spring and said first shoulder are adapted to snugly engage a blade inserted therebetween with said spring affording pivotal compensating movement during axial movement of the blade, said second shoulder being recessed along its upper marginal edge and having a tapered guide and support nodule formed in the recessed portion, said spring providing a second flange extending substantially horizontally over said second shoulder and abutting said nodule and adapted to be maintained thereby in firm alignment with said first shoulder during said pivotal movement of said spring.

9. In a scissors sharpener having a motor casing, a motor mounted within said casing, said motor having a rotatable shaft and an abrasive wheel carried by said shaft, a shoulder formed integrally with said casing and extending into partially overlying relation with said wheel at a predetermined angle relative to the plane of said wheel, a second shoulder extending in substantially parallel spaced relationship to said first shoulder to form a guide way, and a spring secured at one end of said second shoulder and biased into normally abutting engagement with said first named shoulder, said spring having an elongated depending flange extending between said shoulders and having an inclination complementary to the inclination of said first shoulder whereby said spring and said first shoulder are adapted to snugly engage a blade inserted therebetween with said spring affording pivotal compensating movement during axial movement of the blade, said second shoulder being recessed along its upper marginal edge and having a tapered guide and support nodule formed in the recessed portion, said spring providing a second flange extending substantially horizontally over said second shoulder and abutting said nodule and adapted to be maintained thereby in firm alignment with said first shoulder during said pivotal movement of said spring, said wheel being tapered at a predetermined angle complementary to said depending flange and said shoulder for accurate formation of a cutting edge on the blade.

10. In a scissors sharpener having a motor casing, a motor mounted within said casing, said motor having a rotatable shaft and an abrasive wheel carried by said shaft, a shoulder formed integrally with said casing and extending into partially overlying relation with said wheel at a predetermined angle relative to the plane of said wheel, a second shoulder extending in substantially parallel spaced relationship to said first shoulder to form a guide way, and a spring secured at one end of said second shoulder and biased into normally abutting engagement with said first named shoulder, said spring having an elongated depending flange extending between said shoulders and having an inclination complementary to the inclination of said first shoulder whereby said spring and said first shoulder are adapted to snugly engage a blade inserted therebetween with said spring affording pivotal compensating movement during axial movement of the blade, and a third shoulder formed integrally with said first shoulder at a predetermined angle thereto, said third shoulder being adapted to engage a blade not being sharpened on said wheel when a blade being sharpened has been extended its full longitudinal extent over said wheel.

11. In a knife and scissors sharpener having a motor, a housing and an abrasive wheel rotatable by said motor, a circumferential edge on said wheel having a predetermined taper relative to the axis of said wheel, a pair of substantially spaced parallel shoulder forming a guide way in said housing extending into partially overlying relation with said tapered portion at a predetermined angle to the plane of said wheel, and spring means secured at one end to the housing and extending along one of the shoulders adjacent to the wheel including an elongated depending flange adapted to bear resiliently against a blade inserted between said spring and one of said shoulders.

12. In a sharpener for knives and hand scissors having pivoted blades, a housing, a motor therein, an abrasive wheel mounted on the shaft of the motor and rotatable therewith, a circumferential edge on said wheel defining a tapered surface of revolution coaxial with said shaft, a pair of substantially spaced shoulders facing each other and forming a guideway in said housing opening in a direction radial to the wheel at said surface of revolution, one shoulder being fiat and serving as a guide face for the flat surface of one blade of a pair of scissors, said guide face extending across said circumferential edge in a direction disposed at an angle to the plane of the wheel with the plane of the guide face disposed at an acute angle to said surface of revolution at said circumferential edge for establishing a working area thereat for the tapered surface, means normally directing said flat surface of said blade against said guide face in sliding relationship therewith, and means receiving said scissor blade in guided relation upon said guide face with the blade engaging said tapered surface at a point close to the pivot of the scissors including an offset in said one shoulder providing a second shoulder at an angle thereto engaged by the edge of the other scissor blade when the scissor blades are opened wide.

13. In a sharpener for knives and hand scissors having pivoted blades, a housing, a motor therein, an abrasive wheel mounted on the shaft of the motor and rotatable therewith, a circumferential edge on said wheel defining a tapered surface of revolution coaxial with said shaft, a pair of substantially spaced shoulders facing each other and forming a guideway in said housing opening in a direction radial to the wheel at said surface of revolution, one shoulder being flat and serving as a guide face for the flat surface of one blade of a pair of scissors, said guide face extending across said circumferential edge in a direction disposed at an angle to the plane of the wheel with the plane of the guide face disposed at an acute angle to said surface of revolution at said circumferential edge for establishing a working area thereat for the tapered surface, and means receiving said scissor blade in guided relation upon said guide face with the blade engaging said tapered surface at a point close to the pivot of the scissors including an offset in said one shoulder providing a second shoulder at an angle thereto engaged by the edge of the other scissor blade when the scissor blades are opened wide.

14. In a sharpener for knives and hand scissors having pivoted blades, a housing, a motor therein, an abrasive wheel mounted on the shaft of the motor and rotatable therewith, a circumferential edge on said wheel defining a tapered surface of revolution coaxial with said shaft, 8. pair of substantially spaced shoulders facing each other and forming a guideway in said housing, one shoulder being fiat and serving as a guide face for the fiat surface of one blade of a pair of scissors, said guide face extending across said circumferential edge in a direction disposed at an angle to the plane of the wheel with the plane of the guide face disposed at an acute angle to said surface of revolution at said circumferential edge for establishing a working area at the tapered surface, means resiliently exerting a force upon said blade in a direction transverse to said guide face to urge the fiat surface of said blade against said guide face, and means receiving said scissors in guided relation upon said guide face with the blade engaging said tapered surface at a point close to the pivot of the scissors including an offset in said one shoulder providing a second shoulder at an angle thereto engaged by the edge of the other scissor blade when the scissor blades are opened wide.

References Cited in the file of this patent UNITED STATES PATENTS 

